Big Briar CP-251 Control ProcessorIf you want to integrate several analog synths or other devices that you can manipulate using control voltages, Big Briar's CP-251 Control Processor is virtually a must-have. In fact, we wonder why such a thing wasn't marketed 20 years ago.

The CP-251 lets you route control voltage and provides additional modulation sources, such as sample and hold and an LFO. It brings synthlike control to a wide variety of voltage-controlled gear. The unit's onboard CV mixer accepts four CV signals at once. Two of the four inputs deliver +5V to the ring for use with expression pedals; the other pair supplies -5V to the tip for most other CV needs.

The CP-251 offers several onboard modulators. A lag processor with an attack/release envelope generator lets you reshape the control-signal waveform. A white-noise generator serves as an audio source or a randomized control signal. The sample-and-hold circuit is great for producing stepped control waveforms; patching in white noise randomizes sample-and-hold effects. This is big fun when controlling pitch or filter frequencies.

The CP-251 brilliantly borrows from the modular analog synthesis tradition and offers enormous flexibility in reshaping modulation. If a unit that modulates modulators seems abstract, just connect the CP-251 to a signal processor or two, plug in a guitar, and have fun!